This week, HudBay Minerals (NYSE:HBM) drops from C to a D rating. HudBay Minerals is a mining company that mines and produces zinc, copper, gold, and silver. The stock gets F’s in Cash Flow, Margin Growth, and Sales Growth. The trailing PE Ratio for the stock is 254.50. For a full analysis of HBM stock, visit Portfolio Grader.

Pretium Resource (NYSE:PVG) is having a tough week. The company’s rating falls from C to a D. Pretium Resources acquires, explores and develops gold and precious metals resource properties. The stock also rates an F in Cash Flow. The stock price has fallen 6.3% over the past month, worse than the 4.1% increase the S&P 500 has seen over the same period of time. For a full analysis of PVG stock, visit Portfolio Grader.

Tahoe Resources Inc (NYSE:TAHO) gets weaker ratings this week as last week’s C drops to a D. Tahoe Resources acquires, explores and develops resource properties in the Americas for the mining of precious metals, primarily silver. The stock also gets an F in Equity. As of Jan. 7, 2013, 11.5% of outstanding Tahoe Resources Inc shares were held short. For a full analysis of TAHO stock, visit Portfolio Grader.

This is a rough week for Paramount Gold & Silver (AMEX:PZG). The company’s rating falls to D from the previous week’s C. Paramount Gold & Silver explores for precious metals in Mexico. The stock gets F’s in Earnings Growth and Equity. As of Jan. 7, 2013, 11.1% of outstanding Paramount Gold & Silver shares were held short. For more information, get Portfolio Grader’s complete analysis of PZG stock.

This week, Globe Specialty Metals’ (NASDAQ:GSM) rating worsens to a D from the company’s C rating a week ago. Globe Specialty Metals produces silicon metal and silicon-based alloys, which are used in a variety of industrial and consumer products. The stock receives F’s in Earnings Growth, Earnings Momentum, Earnings Revisions, and Margin Growth. The stock currently has a trailing PE Ratio of 40.00. For more information, get Portfolio Grader’s complete analysis of GSM stock.

Louis Navellier’s proprietary Portfolio Grader stock ranking system assesses roughly 5,000 companies every week based on a number of fundamental and quantitative measures. Stocks are given a letter grade based on their results — with A being “strong buy,” and F being “strong sell.” Explore the tool here.